Cushioning mechanism



NOV. 1934- D. c, DAVIS El AL I CUSHIONING MECHANISM Filed Oct. 29, 1927 2 Sheets-Sheet 1 Liiii.

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Q Q ww m Q Q m k Wm m D. c. DAVIS El AL cusHIoNINe MECHANISM Filed Oct. 29, 1927 Patented Nov. 27, 1934 v UNITED STATES- CUSHIONING MECHANISM Donald G. Davis, Depew,

Buffalo, N. Y.,

and Leverett M. Clark,

assignors to The Gould Coupler Comping: New York, N. Y., a corporation of Application October- 29, 1927, Serial No. 229,641

4Claims.

- This invention relates to cushioning mechanism and more particularly to friction draft and buffing gear adapted for use on railway cars.

The principal object of our invention, generally 5 considered, is to provide a friction draft gear particularly adapted for railway service, said gear comprising a casing or barrel open at one end and presenting wearing surfaces for engagement with cooperating wedge blocks, resilient means being provided for spreading said wedge blocks as well as for urging the same toward the open end of said casing, said wedge blocks and/or said wearing surfaces being provided with means for preventing non-uniform frictional resistance therebetween.

' An object of our invention is the provision of a friction draft gear involving a barrel or casing open at one end, said casing being preferablyformed without the usual integral or inclined friction surfaces and instead formed with pockets receiving removable wedge or wear plates which are adapted to present such inclined friction surfaces for engagement with wedge blocks, some of the engaging members being formed with lead inserts which act to provide a coating of lead on the surface thereof and the engaging friction elements for causing uniform frictional resistance therebetween, whereby sticking of the gear is obviated.

Another object of our invention is to provide a gear in which wedge plates are received-in recesses in the barrel or casing and in which said recesses may be longer than the wedge plates whereby a limited longitudinal movement of said wedge plates is permitted in said recesses.

- A further object of our invention is the use of a friction casing or barrel for cushioning mechanism which is substantially rectangular or square in cross-section rather than circular or 40 approximately circular whereby the use of filler blocks heretofore employed is rendered unnecessary.

A still further object of our invention is the provision of cushioning mechanism formed with a casing or barrel open at one end and closed at the other in which said casing is provided with pockets adjacent said open .end receiving friction plates or blocks with the engaging surfaces between said plates or blocks in the barrel curved in a plane transverse to the longitudinal axis of the gear for permitting the equalization thereof, provision being made for. either preventing or permitting longitudinal movement of said friction blocks with respect to said casing.

'55 An additional object of our invention is the provision of a casing for friction draft gear substantially rectangular in cross section witha pair of opposite sides thereof longitudinally ribbed or convoluted for increasing the strength thereof and at the same time centering the inclosed springs. Other objects and advantages of the invention relating to the particular arrangement and construction of the various parts will become apparent as the description proceeds.

Referring to the drawings illustrating our invention, the scope whereof is defined by the appended claims,-

Figure 1 is a side elevation, partly in vertical longitudinal section, of a cushioning mechanism embodying certain features of our invention.

Figure 2 is a partial end elevation of the gear with the rear follower removed and partial transverse sectional view on the line 2-2 of Figure 1, looking in the direction of the arrows.

Figure 3 is a transverse section of the casing or barrel on the line 3-3 of Figure 1, looking in the direction of the arrows.

Figure 4 is a fragmentary longitudinal sectional view corresponding to Figure 1, but showing a modification. I

Figure 5 is a top plan of the wedge plate illustrated in Figure 4. A

Figure 6 is a view corresponding to Figure 1, but showing another modification.

Figures 7, 8 and 9 are transverse sectional views on the lines 7-7, 8-8 and 9-9, respectively, of Figure 6, looking in the direction of the arrows.

Heretofore trouble has been experienced with friction draft gears in which friction wedges have been employed cooperating with a barrel provided with inclined friction surfaces or. containmg friction plates provided with such surfaces due to sticking upon release of the gears. This sticking is apparently caused by a non-uniform coeflicient of frictionbetween the engaging friction surfaces and said surfaces have been found to slide over one another with a relatively small amount of friction for a part of their movement and with a great deal more friction for another part thereof. In accordancewith the present in- 10 vention means are provided for causing the coefllcient of friction to be substantially uniform between the engaging friction elements.

Referring to the drawings indetail, like parts being designated by like reference characters, a draft gear or cushioning mechanism is illustrated comprising a barrel or casing 1, containing parts which will presently be described. Said casing is normally disposed longitudinally between draft sills, not shown, and its front and no rear followers 4, 5, are adapted to be embraced by a yoke, not shown, attached to a draw bar or the stem of a coupler, not shown. Inasmuch as this draft gear is adapted for use between sills normally disposed with a yoke and coupler of normal construction, it is not considered necessary to describe these parts in detail.

One end of the casing, in the present instance shown as the front end 8, although it is obvious that the casing may be reversed end to end, is wholly or partly closed, and a coil spring set 9 which may be of standard construction, preferably consisting of inner and outer coils, is disposed between the closed end 8 and intermediate follower 10. Curved leaf springs or spring plates 11 are arranged to the rear of the follower 10 and act to force apart wedges 12 which have inclined surfaces which frictionally engage similar surfaces either disposed on the spring barrel or casing or on friction blocks or wear plates 13. The rear or outer ends of the wedges 12 are engaged by the rear follower 5, as clearly shown in Figure 1, and in the modified construction illustrated in Figure 6. The springs 11 and the wedges 12 are disposed between the followers 5 and 10.

In previous forms the rear or open end of the casing 1 containing the leaf springs, wedges and wedge plates, has been approximately circular in transverse section and this has necessitated the use of filler plates. In the present instance, in accordance with our invention, the rear end 14 of the casing has a rectangularor approximately square cross section and is clearly shown in Figures 3 and 9 and the springs 11 are so wide that they extend practically from one side wall to the opposite side wall of the square or rectangular part whereby filler plates between the sides of said springs and the adjacent walls of the casing are not required.

The wedge plates 13, as shown in Figures 1 and 6, are received in recesses 15 in the upper and lower walls of the open end or part 14. These recesses are curved transversely, as shown at 16 in Figures 3 and 9, to permit transverse equalization of the wedge plates 13. In Figures 4 and 6, the recesses for the wedge plates are each of a compound nature, involving a forward or inner transverse groove or recess 16* and a rear or outer recess 16, the former receiving a forward or inner hook or nose 13 of the wedge plate and the latter receiving the tail or outer portion 13 thereof for interlockingly holding said plates. In Figure 4 the recesses 16 16 are somewhat longer than the parts which they receive so that the wedge plates are permitted a certain amount of longitudinal movement with respect to the easing 1. It is to be understood that the recesses 16 16 may be transversely curved, as shown at 16, in Figures 3 and 9, for permitting equalization. of the wedge plates.

In accordance with our invention provision is made for treating the engaging surfaces of the wedges 12 and wedge plates 13 to render their frictional resistance more uniform or regular. It has'been found that lead is very satisfactory for this purpose, although we do not wish to be limited to the use of pure lead, as it is within the scope of this invention to utilize an alloy in which lead predominates or is a prominent ingredient or any other substance or alloy in which lead is the active ingredient or which will produce the desired result. It must be understood that the purpose of the invention is not to materially decrease the coefficient of friction between the engaging surfaces, although some decrease may be incidental, but rather to obtain a regular or more uniform frictional action without substantial diminution of the amount of friction set up between the engaging surfaces. Such a result is obtained by the application of such soft metalsas lead and alloys thereof to the steel or iron friction surfaces whereby the interstices in the surfaces become filled to thereby eliminate their cutting tendencies. The true friction characteristics of the adjacent surfaces are thereby not affected by the abnormal friction caused by abrasion. It should be noted, however, that the employment of lead or other soft metals cannot be considered in any sense as true lubrication, and merely eliminates abrasion without materially reducing the true friction between the surfaces. Such employment of lead or the like results not only in the elimination of abrasion, but in stabilizing the normal coefficient of friction of the adjacent-friction surfaces, reducing the static adhesion of adjacent friction surfaces, and assuring positive and prompt release of the friction system using such means.

To this end, wedge plate 13, as shown in Figures 4 and 5, is provided with a transverse undercut groove 1'? in which is inserted a charge of lead or approximately flush lead insert 18. Said lead is conveniently applied by melting and pouring into the groove, but may be applied in any desired manner.

In operation, due to the relative movement and great pressure between the engaging surfaces of the wedges 12 and plates-13, lead is distributed over these surfaces from the inserts which act as reservoirs, filling interstices or irregularities of said surfaces, it being understood that the wedges and plates are customarily made of cast steel, which is a well known form or-compound of iron. Such lead smoothes the engaging frictional surfaces, rendering them more nearly devoid of superficial irregularities and causes the frictional action therebetween to be more regular and uniform.

Instead of being provided in the wedge plates 13, the lead inserts may be provided in the wedges 12, as shown in Figure 6. The invention is notlimited to the provision of a single lead insert in each wedge or wedge plate, as two or more lead inserts may .be used in each wedge or in each plate or in both wedge and plate and maybe arranged in a wide variety of ways. If a friction casing is employed in which the friction surfaces are provided integral thereon rather than on friction plates held in recesses therein, lead inserts may be provided on said integral surfaces. The slots receiving the lead have any desired form and may extend the full width of the wedge or plate or may terminate short of the edges thereof,

as shown in Figure 5. Short slots may overlap 19 of the casing 1, like the rear part 14, is rectangular in cross section. For the purpose of supporting the coil spring 9 the bottom wall or floor of the part 19 has a central longitudinal rib or boss 20 which extends sufficiently toward the open end of the casing to support the intermediate follower 10. In Figures 6, 7 and 8, the forward part of the casing 1 containingthe coil springs and the intermediate follower has a square or rectangular part immediately adjacent to the portion 14 and forwardly of the part 21 the casingv has a partly circular portion 22 as shown in Figure 7. The portion 21, as shown in Figures 6 and 8 has in its top and bottom walls central inwardly extending ribs or bosses 23 between which are received the rear end of the spring 9 and the follower 10. The curved side walls of the forward part 22, as shown in Figure '7, afford sufficient support for the outer springs 9 and the curved side walls are connected at top and bottom by generally flat normally horizontal walls 24.

Although we have disclosed preferred embodiments of our invention, it will be understood that modifications will suggest themselves to those skilled in the art without departing from the spirit and scope of the appended claims.

Having now described my invention, I claim:

1. Cushioning mechanism adapted for use with railway draft rigging comprising a plurality of engaging relatively movable friction elements, at least one of said elements having a groove in its engaged surface and lead filling said groove substantially flush with said surface, to provide a reservoir for distribution of lead over said engaged surfaces by the operation of the rigging.

2. Cushioning mechanism comprising a friction member, a wedge member engaging said friction member with the engaged surfaces forming main energy absorbing means in said mechanism, said engaged surfaces having lead in the interstices between surface projections to minimize their cut ting tendencies, without substantially affecting the true friction characteristics of the wedge and friction member surfaces, whereby sticking and abrasion are minimized, and means forming a supply of lead for distribution over the engaged surfaces during operation of the gear.

3. Cushioning mechanism adapted for use with railway draft rigging comprising friction elements, one of which slides over another when the mechanism is operated, at least one of said elements being provided with at least one slot in the friction surface engaged by another, and lead filling the slotted portion of said element to approximately flush with said surface, in order to avoid sticking between said friction elements, said lead extending transversely of the line of relative sliding for substantially the entire width of the friction surface, to provide a supply for the efficient distribution of lead over said engaged surfaces during the operation of the mechanism.

4. Cushioning mechanism adapted for use with railway draft rigging comprising friction elements each having a friction surface, one of which slides relative to another when the mechanism is operated, one of said elements being provided with a slotted portion in its friction surface, said slot ex tending at an angle to the direction of movement between the surfaces, and lead filling said slotted portion to a point approximately flush with and extending substantially the entire width of, said friction surface, whereby a supply of lead particles is provided for distribution over said engagin surfaces, to avoid sticking between said surfaces during the operation of the gear.

DONALD C. DAVIS. LEVERETT M. CLARK. 

